Portable motor operated hand scroll saw



p 1951 J. L. BECHTOLD 2,547,922

PORTABLE MOTOR OPERATED HAND SCROLL SAW Filed Jan. 30, 1948 3Sheets-Sheet 1 Inventor 5 Joseph L Bach/old April 10, 1951 J. BECHTOLDPORTABLE MOTOR OPERATED HAND SCROLL SAW 3 Sheets-Sheet 2 Filed Jan. 30,1948 Iuventar Joseph L. Bach/old and April 1951 J. L. BECHTOLD 2,547,922

PORTABLE MOTOR OPERATED HAND SCROLL SAW Filed Jan. 30, 1948 3Sheets-Sheet 3 Fig. 3 53 Fig. 4.

4- m l/4. VIII/4 i Joseph L Bach/old Attorneys Patented Apr. 10, 1951OFFICE PORTABLE MOTOR OPERATED HAND SCROLL SAW Joseph L. Bechtold,Roseburg, Oreg. Application January 30, 1948, Serial No. 5,279 I 3Claims. (Cl. 14368) My invention relates to improvements in portablemotor operated, hand scroll saws for cutting sheet material, especially,although not necessarily.

The primary object of my invention is to provide a simple form ofinexpensive hand scroll saw with a motor drive and which is betteradapted for scroll sawing sheet material than stationarily mountedscroll vsaws, is not liable to get out of order, and is designed forsmooth operation with a reciprocating saw blade.

Other and subordinate objects, within the purview of my invention,together with the precise nature of my improvements will be readilyunderstood when the succeeding description and claims are read withreference to the drawings accompanying and forming part of thisspecification.

In said drawings: I

Figure 1 is a view in vertical section, with parts shown in elevation,of my invention in a preferred embodiment thereof;

Figure 2 is a fragmentary view in vertical section taken on the line 22of Figure 1;

Figure 3 is a fragmentary view in vertical section taken on the line 3-3of Figure 2 with parts eliminated for clearness of illustration;

Figure 4 is a fragmentary view in horizontal section taken on the line4-4 of Figure 1,

Figure 5 is a detail fragmentary view in plan, partly broken away andshown in section;

Figure 6 is a view in vertical section taken on the line 66 of Figure 1;

Figure 7 is a view in front elevation drawn to a smaller scale,andpartly broken away.

Referring to the drawings by numerals, according to my invention, asillustrated, a hand scroll saw is provided comprising a generallyrectangularbase, shoe plate I with upturned front and rear ends 2, 3adapting the same to be slid over sheet material to be sawed.

The shoe plate I has formed thereon, adjacent what constitutes the outerside edge of the same, an aperture 4 in which'the usual saw blade 5 isreciprocated vertically, by means presently described, in a plane at aright angle to the plane of said plate. Between the aperture 4 and therear side edge of said plate I is an elongated cast bracket 5 upstandingfrom said plate to extend longitudinally thereof parallel with the sideedges of the plate and terminating at the rear end of said plate I in aloop handle I. Screws 8 secure the bracket 5 on said plate I.

A motor casing 9 of generally cylindrical shell form, with a closed rearend I0, and internal front end lugs II, extends endwise across thebracket 6, and across said plate I, forwardly of the handle 1 and has apending bottom lug I2 pivoted by a pivot pin I 3 in said bracket 6 sothat the motor casing 9 is tiltable vertically about an axis transverseto said plate I and parallel with of said plate over the work. Asuitable wing head latching bolt I4 threaded into the bracket 6 to beturned against the lug I2 is provided for retaining the motor casing 9in different tilted positions, for a purpose presently seen.

A substantially annular plunger head I5 with an open front side I5,vertically aligned top and bottom bosses II, I8 thereon and a closedrear side I9 is fixed to the front end of the motor casing 9concentrically thereof by screws 20 passing through said side I9 andinto the lugs II. A closure plate 2| is secured to the front side I5 ofsaid head I5 by screws 22. As will be seen, the described head I5 istiltable with the motor casing 9.

An electric motor 23 is secured in the motor casing 9 with its armatureshaft 24 coaxial with that of said casing and running in a bearing 25provided in the rear end ID of said casing 9 and adapted to belubricated through an oil plug 26. Lugs 21 on the front end of the motor23 are bolted, as at 28, to a cross support 29 in said the line ofmovement motor casing 9.

A train of reduction gearing 30 in the front end of the motor casing 9operatively connects the armature shaft 24 to a short driven shaft 3|journalled in the rear side I9 of said head I5 in axial alignmentwithsaid shaft 24. duction gearing 30 comprises a pair of relatively smalland large driving and driven gears 32, 33 fast on the, armature shaft 24and driven shaft BI and a pair of reduction gears 34 meshing,respectively, with the gears 32, 33 and fast on a shaft 35 journalled inthe cross support 29 and in abearing 36 in said casing 9.

,An eccentric 3'! is fast on the front end of the driven shaft 3|, insaid head I5, in the rear of the head, also a fly wheel 38 between theeccentric 31 and the rear side I9 of said head I5 suitably counterweighted, as shown at 39, to counter balance the eccentric 31.

The eccentric 3! fits and revolves between a pair of vertically spacedcollars 40 fixed by pins 4| on a verticalplunger shaft 42 arranged toreciprocate and rotate in the vertical axis of the head I5 and theaperture 4 with its lower end extending through and below boss I8 by wayof a guide bore 43 in said boss, said saw blade 5 being secured in avertical slot 44 in the lower end of said shaft by screws 45.

. The plunger shaft 42 terminates at its upper end in said head I5 andis rotatable in said bore 43 and in a pair of upper and lower sectionalcap bearings 46, 41 secured together and to the rear side I9 of the headI by bolts 48. Lubricating glands 49', 50' are threaded in the upper andlower bearings 46, 41 against packing 49, 50.

A pair of upper and lower expansion coil springs 5|, 52 surround theplunger shaft 42, one inter- The remediate the upper collar 40 and thebearing 46, and the other intermediate the lower collar 40 and the gland50, and which balance said shaft in an intermediate normal position.

Means are provided for setting the plunger shaft 42 into differentangular positions, by rtating the same to correspondingly set the saw'blade and now to the head I5 is a hand wheel 53 fast on the upper end ofa saw setting shaft 54 vertically aligned with the plunger shaft 42and'havingxa lower squared end 55 slidable in a square axial socket 56provided in the upper, The saw setting shaft 54*is rotatable in apackin'g gland 51 set into the upper b'oss- H with the setting shaft54'extending therethro'ugh into said head 15. A cap plate 58 on saidbossll secured thereto by screws 59*retains th'e' packing gland 51 inits place. A collar BO 'fixe'd to said'shaft 54 as at 66 and forming 51prevents upward thrust of said shaft 54. A hub 6l-on the hand wheel 53prevents downward play' of said shaft 54; A cam 62 with a hand lever 63thereon is pivoted as'at 64, on top of the cap plate 58 to be wedgedagainst the hub 61 and thereby hold the hand wheel53, the saw settingshaft-54, and plunger shaft 42 and saw'blade 5 in different'setpositions irf which the saw blade 5 is oblique to the line of movernentofthe shoe plate I. v I

A suitable switch 55 operated byafinger piece 66-is provided onthehar'idle 'l for controlling the motor 23 which may be provided withthe usual plug in leadcables, not shown;- for connection to a wallsocket, or'the like, not shown. 7

In operatingthe described hand scroll saw, the same is pushed along thework, not shown, with the shoe plate I sliding over the work; motor 23running} the plunger shaft is reciprocated with the saw blade 5 by theeccentr'ic'3'l working between the collars and in opposition to thesprings 52,52 which'te'nsion said shaft 42 against movement in oppositedirections'fr'om in termediate positions so that said springs functionin reciprocating said' plunger shaft and to take part of the load off'themotor 23. The-described reduction gearings' 30" provid'e'jfor theuseof a' high speed motor 23 with" slower reciprocation of the saw'5 aswill be apparent; During recipro cation of the plunger shaft42, the sameslideson the squared end 55 of the saw setting shaft 55. By setting thehand wheel 54, in the manner described the saw blade 5 may be adjustedto different angular positions 111 scroll sawing, or

like work. By tilting the motor casing 9into dif ferent set positions onthepiris' -l3, and asdetermined by use of be correspondingly tilted 42and the saw blades 5 laterally of-the'lineof the cut as occasion mayrequire in scroll sawing Work.

The foregoing will, iti's believed, suffice to impart a clearunderstanding of my invention, without further explanation.

Manifestly, the invention, as'described, is sus'-' ceptible ofmodification, without'departing'from the inventive concept, and'right isherein re served to such modifications'as fallwithin the scope of theappended claims.

Having described my invention, as new is:

what is claimed be described. At the top of end of said shaft 42' partof the said-gland With the' locking bolt IA, the'head |5 may to tilt theplunger shaft ed to extend out of the head, a saw 1. In a saw of theclass described, a motor cas-' ing having a motor therein, a hollow headfast on said" casing, 'a reciprocating and rotatable plunger shaft insaid head having one end adaptblade fixed to' said end of said shaft inlongitudinal alignment therewith', a drive between said motor andshaftfor reciprocating said shaft, a shoe plate for sliding movementover the work, means to 'rrioun't said casing on said plate for tiltingof the sam'e together with said head, shaft and blade laterally of theline of movement of said plate, and'means to rotate said shaft intodifferent set angular positions to correspondingly set said blade indifferent oblique-positions relative to theline of movement of theplate.

2. In a saw of the class described, a motor casing having a motortherein, a hollow head on' said casing, a reciprocating and rotatableplunger-shaft in said head having one end adapted to extend out of thehead, a saw blade fixed tosaid end of saidshaft'in longitudinal align--ment therewith, a drive'between said motor and shoe platefor'saidcasi'ng and head and for slid ing movement ov'er the work, andmeans connected to; the opposite end of said-shaft for rotating the-sameinto different angular set positions to correspondingly set said bladeinto different oblique positions relative to the line of movement ofsaid plate comprising a hand wheel rotatable on said head, a settingshaft'rotatable by said wheel and splined in said opposite end of theplunger shaft, and a pivoted cam on said head for locking said wheel.

3. In-asaw of the class'describ'ed, a motor casing having a motortherein, a hollow head on sai'd'ca'sin'g', a reciprocating and"rotatableplunger shaft in said head having one end adapted to ex tendout of the head, a saw blade'fixed to said end of said shaft inlongitudinal alignmen't'therewith, a drive between-said motorand-Shaftfo'r reciprocating the shaft; means supporting said casing andhead for work, and means connected tothe' opposite end of said shaft forrotating thesame into different angular set positions to correspondinglyset said blade into different oblique position's'relative tothe line ofmovement of said head comprising a handwheel rotatable on saidheadymeans con necting said wheel-to said shaft to rotate'said' shaftwhile reciprocating and by rotation ofsaid wheel, and a pivoted cam-onsaid head' for lock-- ing said wheel.

. JOSEPH nBEcn'roLD.

REFERENCES; CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number 7 Name Date 216,245 Warth June 3,- 1879620,847 Jackson Mar; 7, 1899 824,948 Pollock July 3, 1906 1,707,097Ruschke Mar. '26, 1929 1,808,228" Hula'ck'et al June'2, '1931 1,974,642Colby Sept. 25, 1934 sliding movement over the

